The invention relates generally to coils such as end windings of machines such as AC motors, generators, and transformer coils. More particularly, the invention relates to a tool and a method for cutting coils such as end windings to facilitate removal for repair and maintenance.
Dynamoelectric machines such as electric generators and motors include a rotor and a stator. Rotors are generally constructed from a steel forging and include a number of slots that run the length of the rotor. Rotors are electrically wound by placing conductors referred to as rotor windings into the slots of the rotor. Stators are generally constructed from a number of stacked, metal laminations. Stators also include slots, which run the length of the stator, and are electrically wound by placing conductors known as stator coils into the slots of the stator.
In response to wear, stator coils must be removed from the stator and replaced periodically. Such removal has been accomplished by cutting end windings using a reciprocating saw, and removing the cut coil ends. Cutting the end windings with a reciprocating saw generates dust which contaminates the environment and creates environmental, health, and safety concerns. Additionally, in cases in which coils are insulated using asbestos insulation, the use of a reciprocating saw and the resultant dust may be particularly problematic. It also causes operator fatigue, which carries a risk of operator injury. Additionally, this method is often time consuming, as the end windings must be cut individually. This situation contributes to increased down time for the machine, and therefore added cost. End windings have also been cut using a scissor-action cutter, which is impractical when coils are located in narrow slots or spaces, leaving no room for a scissor-action cutter to operate.